Fuel control for combustion apparatus



" Nov. 21,1944.

J. W. MILLER ETAL FUEL CONTROL FOR COMBUSTION APPARATUS 2 Sheets-Sheet 1 Filed Feb. 3, 1941 IN VEN 10R. 14/. M/LL 2? 2224 JOHN BY FAG/MONO 5 F524 1 Nov. 21, 1944. J. w. MILLER ETAL FUEL TcoNTRoL FOR COMBUSTION, APPARATUS Filed F eb."3,' 1941 ,2 Sheets-Sheet 2 INVENI'OR.

BY PAY/vamp E FELL $164- ATTORNEY.

'Wide variation in heat output.

Patented Nov. 21,

UNITED" STATES PAT ENT. OFFICE FUEL qou'mor. FOR COMBUSTION APPARATUS John W. Miller and.Ray

mond E. Fell, Lansing,

Mich., assignors to Motor Wheel Corporation, Lansing, Mich., a corporation of Michigan Application February 3, 1941, Serial No. 377,116 8 Claims. (Cl. 158- 91) This invention relates to combustion apparatus employing liquid fuel burners capable of opera ployed in combustion apparatus of the type to i which this invention relates are capable of a The output of the burners is primarily governed by the quan-- tity of fuel supplied thereto, and may be controlled by varying the rate of delivery of fuel to the burner.

For maximum efllciency of operation the air needed for combustion of the fuel must ,be supplied to the burner in the proper quantities to completely consume the fuel. Provision for control of the air supply usually has been provided in the form of an automatic draft regulator 10- catedin the flue outlet from the combustion chamber of the apparatus, although other forms of control devices have been employed. Such control devices can be adjusted to vary the draft on the burner, and consequently the supply of air, in accordance with requirements for best efflciency. Once adjusted, the draft is maintained practically constant.

Thus, in order to obtain maximum efllciency, it is necessary to adjust the draft regulator every time the fuel flow is changed and to adjust the fuel control every time the draft is changed. It isdifllcult for an operator to coordinate'th'e two controls by manual adjustment of each unless they have been calibrated so as'tp indicate whenthey are properly coordinated. Even then, some operators will not take the trouble to adjust the other control every time one of them is changed.

Accordingly, the principal object of the present invention is to provide mechanism for automatically coordinating the fuel and air supplied to a burner whereby maximum efliciency at all stages of operation of the burner is obtained.

Another object of the invention is to provide means whereby the heat output of the burner can be regulated merely by controlling the draft thereon.

Still another object is to provide means whereby in combustion apparatus having draft regulating mechanism, the supply of fuel to the burner is automatically varied in accordance with changesin the draft produced by said regulating mechanism.v 1

Briefly, the invention comprises mechanism as.

sociated with the combustion apparatus in such a way that it is operated by changes in draft, and is coupled to the fuel regulating system whereby an increase in the draft causes a corresponding. increase in the fuel supply, or a decrease in draft causes a corresponding decrease in the fuel supply.

The foregoing objects, and others more or less ancillary thereto, will more fully appear in the following specification, when read in connection .with the accompanying drawings, wherein:

Figure 1 is a fragmentary elevational view of I a circulating heater embodying the invention;

Figure 2 is a cross-sectional view of the apparatus shown in Figure 1 taken on the 1ine2-2 of Figure 1; v

Figure 3 is a fragmentary elevational view, with parts broken away, of a modified form of the invention; and, V

Figure 4 is a cross-sectional view taken on substantially the line 4-4 of Figure 3.

The combustion apparatus disclosed in Figure 1 comprises a circulating heater having an outer casing llland an inner shell II. The latter is divided into a combustion chamber [2 and an air jacket l3 by an annular shoulder IS. A vaporizing pot type burner 15 is located within the air jacket and held in tight engagement with the shoulder M by a bottom 'wall IS in telescopic engagement'with the lower end of the shell II. Thei-bottom wall I6 has a large central opening "therein to permit the entry of air to the air jacket IS. The bottom wall It is in telescopic engagement withthe lower end of outer casing l0 also, and is provided with openings ill to permit the circulation of air between the casing l0 and shell I I.

The burner l5 ispreferably of the type dis- 7 closed in Valjean Patent No. 2,186,156, granted with a metering valve 26- operating vertically relative to a valve seat 21. The valve is normally urged vertically upward "by a coil spring 28. Leading from the" valve seat 21, and connecting the fuel control 25 to the burner, is atpipe 29 through which fuel is admitted to the burner. Thefuel control 25, here shown, is of the constant level type, wherein a supply of oil is maintained at a level above the pipe connection 23a so that oil will flow to the burner.

The flow of fuel to the burner is regulated by 'vertical movement of the valve 26, upward movement opening the valve and downward movement closing it. I

Combustion chamber l2 communicates with a chimney 22 through a flue outlet 23. In a side increase in heat from the heater is desired, the

draft on the burner can be varied by rotating'the knob 3| to admit more or less air to the flue outlet through the draft regulator. The draft regulator,

when once set, maintains a substantially constant draft on the burner.

Heretofore it has been necessary in apparatus of the type just described, when increasing or decreasing the output of the heater, to adjust separately both the fuel control and the draft regufuel control.

The apparatus shown in Figures 1 and 2 com prises a sheet metal. housing 32 having parallel side walls 33, and an arcuate bottom wall 34. It also has an upright front wall 35 and a top wall 36 having an opening 3"! therein. Preferably all of the walls mentioned are tightly sealed together whereby the only means for admission of air to the housing is through opening 31.

Pivotally mounted. within the housing on a shaft 38 is a van 39. The vane fits the side and bottom walls 33 and 34 respectively as snugly as possible, while still permitting the vane to pivot about its axis 38. The vane divides the housing into a high pressure section 45 and a low pressure section 46. nected to the vane 39 to substantially balance it.

The housing 32 is connected to the flue outlet 23 and communicates therewith through a duct.

4| opening into the flue outlet.

A counterweight 40 is con- 7 knob 3| is rotated to increase the draft on the burner. 'The increased draft will swing the vane 39still farth'er, thus lifting the lever 44 to a higher position and admitting more fuel to the burner. Conversely, a decrease in the draft occasioned by movement'of knob 3| will diminish the flow of fuel.

- For-proper results, the size and weight of the vane the weights of the counterbalance 46,

crank arm 42, rod 43' and lever 44, as well as the stiffness of spring 28, must be properly chosen so that the entire device is in proper balance at-zero draft.

The modified form of the invention shown in Figures 3 and 4 is used in connection with combustion apparatus identical with that previously described. Only a part of the heater is shown. It comprises an outer casing l6, an inner shell l, abottom wall I6 and a burner l5. The inner shell is connected to a chimney by a flue outlet having an automatic draft regulator, such as draft regulator 30 described above.

Fuel is supplied to the burner l5 through pipes 24' and 29' and a fuel control'25'. Within the fuel control is a valve 26 having a spring 23' sur- On one end of th shaft 38 outside of the houssome oil is admitted to the burner by lifting the rod 43 manually for a short interval. The bumer is then lighted, and the ensuing heated air pass- .ing up the chimney 22 creates a draft on the burner. This draft, or pressure difference, between the interior and exterior of the burner operates on the vane 39 tending to swing it counter-clockwise (as viewed in Figure 2). This raises lever 44 which permits the spring 28 to open valve 26 and admit fuel to the burner. It

will be obvious that any given draft will swing the vane 39 just so far and open the valve 26 a corresponding amount, which it will maintain as long as the draft is constant.

If a greater flow of fuel, and a consequent therefore in open communication with the rounding it and tendingto open the valve.

Mounted on top of the fuel control 25 by means of a bracket 50 is a draft actuated fuel control regulatingdevice. It comprises a sheet metal housing 5| composed of two relatively large dish shaped halves 52 and'53. The halves 52 and 53 are provided with radialperipheral flanges 54 and 55. Within the housing 5| is a large and exceedingly flexible diaphragm .56. The periphery of the diaphragm is located between the flanges 54 and 55 and-the latter are bolted or otherwise secured together. The diaphragm 56 and the half 53 together form a low pressure section of the housing 5|. The diaphragm 66' and half 52 providea high pressure section of the housing. The diaphragm has a very small aperture 56a therein to permit bleeding of air from the high pressure section to the low pressure section. Secured to the diaphragm is a reenforcing sheet 5 'An adjusting screw 58 is threaded into' a bushing 59 in the'center of half 53 of the housing 5| and extends into the housing. A spring retainer 66 is mounted on the inner end of the adjusting screw 58 and avery light spring 6| is interposed between the spring retainer and the diaphragm. Secured to. the center of the diaphragm 56 is a rod .62 which extends through a hole in the half 52 of the housing and the bracket 50. The outer end of the rod 62 passes through a hole in an L shaped 'lever 63. A pair of adjusting buttons 64 are'threadedly orlfrictlonally secured to the 'rod 62 on opposite sides of the lever 63.

The lever 63 is pivoted at 65 to the top of the fuel control and rests on the upper end of the valve 26'.

The half 53. forming the low pressure section of the housing is connected by a pipe 66 and suitable couplings to the fuel feed pipe 29", and is burner. Of course, the low pressure section may. if desired, be connected by pipe 66, or its equivalent, to any other part of the apparatus, so long as the low pressure side is under the influence of the low' pressure within the combustion apparatus. Half 52, the high pressure section of the housing, is open to the atmosphere through the hole through which the rod 62 extends and burner.

through aspecial opening 61 provided for that purpose in section 52.

The operation of the burner I is the same as .that of burner IS. The draft on the burner is regulated by a draft regulator, such as that described in connectionwith the form of the invention shown in Figures 1 and 2.

When a draft has been created, it takes over control of the fuel supply to the burner. The air pressure within half 53 of the housingfil will be substantially that within the burner, while the,

pressure in half 52 will be atmospheric pressure. The diaphragm will move toward .the left (in Figure 4) against the action of spring 6|, thereby pulling on rod 62 and lifting lever 63. This will permit the valve 26' to open. The position of the diaphragm will change every time the draft changes, either permitting valve 26' to open,

. or closing it.

Since the draft, or pressure difference, between the inside and outside of the apparatus is not very great,the diaphragm must be quite large and very flexible.- It may be made of vellum or like material.

Initial adjustment of the draft to the oil flow may be made by moving the buttons 66 on the rod 62, as well as by changing the compressure of spring 6! by the screws 58. 'By manual manipulation of one or the other of these parts. sufllcient oil can be admitted to the burner to initiate combustion. As soon under way,'the draft regulator takes over control of the flow of fuel.

In the form of the invention shown in Figures 3 and 4,the part of the fuel pipe 29"a leading horizontally into the burner is rarely completely filled with fuel, It is filled only when for some reason the burner becomes flooded. Thus, under ordinary circumstances the draft within the burner is communicated to' the diaphragm. If the burner does become flooded so that the pipe 29'a is filled with fuel, then the draftno longer operates on the diaphragm and the valve 25' is permitted to close, shutting off the fuel flow until sufficient fuel in the burner is consumed to open pipeZB'a and permit the draft in the burner to act on diaphragm 56. The aperture 56a in the.

V pivotal movement of as combustion gets a 3 The scope of the invention is indicated in the appended claims.

I claim: g

1. Combustion apparatus comprising a liquid fuel burner, a combustion chamber thereabove, a'fiue outlet from the combustion chamber, an

adjustable automatic draft regulator associated with said flue outlet for controlling the draft on the burner, means including an adjustable metering valve,for supplying fuel to the burner in regulatable quantities, and mechanism con-" nected to the.metering valve and actuated by the draft on the burner for adjusting the metering valve to vary the rate of supply of fuel to the burner in response tovariations in the draft on the latter;- said means including, a housing, a

vane pivotally -mounted in said housing and dividing the latter into a high pressure section 'and a low pressure section, said high pressure adjustable means associatedwith the burner for controlling the draft thereon, a housing, a flexible diaphragm within said housing dividing the latter into a high pressure section and a low pressure section, said high pressure section being in open communication with the atmosphere and said low pressure, section communicating solely with said burner, and mechanism connecting said diaphragm to said metering valve whereby to adjust,the latter to control the rate of supply of fuel to the burner in response to variations in the draft thereon.

3. Combustion apparatus comprising a liquid fuel burner, a combustion chamber communicating therewith and having a flue outlet, means for varying the draft on the burner including an adjustable draft regulator associated with the flue outlet, means including an adjustable diaphragm permits air to leak from the high pressure section to the low pressure section so that the diaphragm may return to its normal position. This feature of the invention is an important safety factor. Without it, diaphragm 56 would become locked. so to speak, in the position it occupied at the time fuel pipe 29'a became filled with fuel. The reason that the. draft is not communicated to the diaphragm ,when the pipe 29',a is filled with'fuei is that the diflference between the atmospheric pressure on one side ofthe diaphragm and the sub-atmospheric pressurein the burner is not great .enough to push the liquid in the pipe 29'a out of the way. .Burners of this type operate normally under a draft of around .08 inch of water, while the maximum draft is about .12 inch of water. a

From the foregoing it will be seen that this invention provides a means for automatically coordinating the fiow of fuel to theburner and the air required to consume-it. It therefore eliminates errors usually occurring in themanual' setting of two separatecontrol means. Further: more, it minimizes the number :of controls that must be operated to regulate the outputof the metering valve connected to the burnerfor supplying fuel thereto in regulatable quantities, and

mechanism for adjusting the metering valve-to vary the supply of fuel to the burner in accordance with variations in the draft on the burner,

said mechanism comprising a housing, means dividing said housing into a high pressure section open to theatmosphere and a low pressure section communicating with the interior of the combustion chamber, said dividing means being connected to said metering valve and movable under the. influence of variations in the pressure difference between the high and low pressure sections of the housing to adjust said valve.

' 4. Conibustion'apparatus as defined in claim 3 whereinsaidv dividing means comprises a diaphragm havinga small opening therein providing restricted communication between said sections. 5. Combustion apparatus as defined in claim 3 wherein said housing is connected to said 'flue outlet.

6. Combustionapparatus comprising a liquid fuel burner, a combustion chamber communicating therewith and having a flue-outlet, means for varying the draft on the burner including an adjustable draft regulator associated with the flue outlet, means for supplying fuel to the burner in regulatable quantities including an adjustable metering valve and a conduit connecting said valve. to the burner above the normal level of fuel therein, and mechanism for adjusting the metering valve to vary the supply of fuel to the burner in accordance with variations in the draft on the burner, said mechanism comprising a housing, means dividing the housing into a high pressure section open to the atadjustable metering 'valve connected to the mosphereand a low pressure section, a conduit connecting said low pressure section with said first mentioned conduit and thereby communicating with the interior of the burner, said dividing means being connected to the metering valve and movable under the influence of variations, in the pressure diflerence between the high and low pressure sections'of the housing.

7. In combination, combustion apparatus in cluding a liquid fuel burner and a combustion chamber having a flue outlet connected together to provide an apparatus having a pressure difierential between its interior and its exteriorduring operation of the burner, means including an burner for supplying fuel thereto in regulatable quantities and pressure responsive means 10- cated exteriorly of the apparatus and communieating with the interior of the apparatus including a member adapted to be moved by changes in the pressure differential between the between the interior and exterior of the apparatus. Y

JOHN w, m RAYMOND E. FELL. 

